I love this Geometric Shapes chart shared by Kathryn on Kindergarten Kindergarten! I had to scroll down to find it, but found a ton of great ideas along the way. I also loved her shape museum. (She has lots of free ideas for teaching math concepts.
Awesome Roll and Cover Shape Game! Roll the dice, add the numbers together and cover the sum. Fun math center or addition idea. Algebra standard: Use mathematical models to represent and understand quantitative relationships.